git.oblomov.eu Git - git/blob - builtin/pack-objects.c

   1 #include "builtin.h"
   2 #include "cache.h"
   3 #include "attr.h"
   4 #include "object.h"
   5 #include "blob.h"
   6 #include "commit.h"
   7 #include "tag.h"
   8 #include "tree.h"
   9 #include "delta.h"
  10 #include "pack.h"
  11 #include "pack-revindex.h"
  12 #include "csum-file.h"
  13 #include "tree-walk.h"
  14 #include "diff.h"
  15 #include "revision.h"
  16 #include "list-objects.h"
  17 #include "progress.h"
  18 #include "refs.h"
  19 #include "thread-utils.h"
  20
  21 static const char pack_usage[] =
  22   "git pack-objects [ -q | --progress | --all-progress ]\n"
  23   "        [--all-progress-implied]\n"
  24   "        [--max-pack-size=<n>] [--local] [--incremental]\n"
  25   "        [--window=<n>] [--window-memory=<n>] [--depth=<n>]\n"
  26   "        [--no-reuse-delta] [--no-reuse-object] [--delta-base-offset]\n"
  27   "        [--threads=<n>] [--non-empty] [--revs [--unpacked | --all]]\n"
  28   "        [--reflog] [--stdout | base-name] [--include-tag]\n"
  29   "        [--keep-unreachable | --unpack-unreachable]\n"
  30   "        [< ref-list | < object-list]";
  31
  32 struct object_entry {
  33         struct pack_idx_entry idx;
  34         unsigned long size;     /* uncompressed size */
  35         struct packed_git *in_pack;     /* already in pack */
  36         off_t in_pack_offset;
  37         struct object_entry *delta;     /* delta base object */
  38         struct object_entry *delta_child; /* deltified objects who bases me */
  39         struct object_entry *delta_sibling; /* other deltified objects who
  40                                              * uses the same base as me
  41                                              */
  42         void *delta_data;       /* cached delta (uncompressed) */
  43         unsigned long delta_size;       /* delta data size (uncompressed) */
  44         unsigned long z_delta_size;     /* delta data size (compressed) */
  45         unsigned int hash;      /* name hint hash */
  46         enum object_type type;
  47         enum object_type in_pack_type;  /* could be delta */
  48         unsigned char in_pack_header_size;
  49         unsigned char preferred_base; /* we do not pack this, but is available
  50                                        * to be used as the base object to delta
  51                                        * objects against.
  52                                        */
  53         unsigned char no_try_delta;
  54         unsigned char tagged; /* near the very tip of refs */
  55         unsigned char filled; /* assigned write-order */
  56 };
  57
  58 /*
  59  * Objects we are going to pack are collected in objects array (dynamically
  60  * expanded).  nr_objects & nr_alloc controls this array.  They are stored
  61  * in the order we see -- typically rev-list --objects order that gives us
  62  * nice "minimum seek" order.
  63  */
  64 static struct object_entry *objects;
  65 static struct pack_idx_entry **written_list;
  66 static uint32_t nr_objects, nr_alloc, nr_result, nr_written;
  67
  68 static int non_empty;
  69 static int reuse_delta = 1, reuse_object = 1;
  70 static int keep_unreachable, unpack_unreachable, include_tag;
  71 static int local;
  72 static int incremental;
  73 static int ignore_packed_keep;
  74 static int allow_ofs_delta;
  75 static struct pack_idx_option pack_idx_opts;
  76 static const char *base_name;
  77 static int progress = 1;
  78 static int window = 10;
  79 static unsigned long pack_size_limit;
  80 static int depth = 50;
  81 static int delta_search_threads;
  82 static int pack_to_stdout;
  83 static int num_preferred_base;
  84 static struct progress *progress_state;
  85 static int pack_compression_level = Z_DEFAULT_COMPRESSION;
  86 static int pack_compression_seen;
  87
  88 static unsigned long delta_cache_size = 0;
  89 static unsigned long max_delta_cache_size = 256 * 1024 * 1024;
  90 static unsigned long cache_max_small_delta_size = 1000;
  91
  92 static unsigned long window_memory_limit = 0;
  93
  94 /*
  95  * The object names in objects array are hashed with this hashtable,
  96  * to help looking up the entry by object name.
  97  * This hashtable is built after all the objects are seen.
  98  */
  99 static int *object_ix;
 100 static int object_ix_hashsz;
 101 static struct object_entry *locate_object_entry(const unsigned char *sha1);
 102
 103 /*
 104  * stats
 105  */
 106 static uint32_t written, written_delta;
 107 static uint32_t reused, reused_delta;
 108
 109
 110 static void *get_delta(struct object_entry *entry)
 111 {
 112         unsigned long size, base_size, delta_size;
 113         void *buf, *base_buf, *delta_buf;
 114         enum object_type type;
 115
 116         buf = read_sha1_file(entry->idx.sha1, &type, &size);
 117         if (!buf)
 118                 die("unable to read %s", sha1_to_hex(entry->idx.sha1));
 119         base_buf = read_sha1_file(entry->delta->idx.sha1, &type, &base_size);
 120         if (!base_buf)
 121                 die("unable to read %s", sha1_to_hex(entry->delta->idx.sha1));
 122         delta_buf = diff_delta(base_buf, base_size,
 123                                buf, size, &delta_size, 0);
 124         if (!delta_buf || delta_size != entry->delta_size)
 125                 die("delta size changed");
 126         free(buf);
 127         free(base_buf);
 128         return delta_buf;
 129 }
 130
 131 static unsigned long do_compress(void **pptr, unsigned long size)
 132 {
 133         git_zstream stream;
 134         void *in, *out;
 135         unsigned long maxsize;
 136
 137         memset(&stream, 0, sizeof(stream));
 138         git_deflate_init(&stream, pack_compression_level);
 139         maxsize = git_deflate_bound(&stream, size);
 140
 141         in = *pptr;
 142         out = xmalloc(maxsize);
 143         *pptr = out;
 144
 145         stream.next_in = in;
 146         stream.avail_in = size;
 147         stream.next_out = out;
 148         stream.avail_out = maxsize;
 149         while (git_deflate(&stream, Z_FINISH) == Z_OK)
 150                 ; /* nothing */
 151         git_deflate_end(&stream);
 152
 153         free(in);
 154         return stream.total_out;
 155 }
 156
 157 /*
 158  * we are going to reuse the existing object data as is.  make
 159  * sure it is not corrupt.
 160  */
 161 static int check_pack_inflate(struct packed_git *p,
 162                 struct pack_window **w_curs,
 163                 off_t offset,
 164                 off_t len,
 165                 unsigned long expect)
 166 {
 167         git_zstream stream;
 168         unsigned char fakebuf[4096], *in;
 169         int st;
 170
 171         memset(&stream, 0, sizeof(stream));
 172         git_inflate_init(&stream);
 173         do {
 174                 in = use_pack(p, w_curs, offset, &stream.avail_in);
 175                 stream.next_in = in;
 176                 stream.next_out = fakebuf;
 177                 stream.avail_out = sizeof(fakebuf);
 178                 st = git_inflate(&stream, Z_FINISH);
 179                 offset += stream.next_in - in;
 180         } while (st == Z_OK || st == Z_BUF_ERROR);
 181         git_inflate_end(&stream);
 182         return (st == Z_STREAM_END &&
 183                 stream.total_out == expect &&
 184                 stream.total_in == len) ? 0 : -1;
 185 }
 186
 187 static void copy_pack_data(struct sha1file *f,
 188                 struct packed_git *p,
 189                 struct pack_window **w_curs,
 190                 off_t offset,
 191                 off_t len)
 192 {
 193         unsigned char *in;
 194         unsigned long avail;
 195
 196         while (len) {
 197                 in = use_pack(p, w_curs, offset, &avail);
 198                 if (avail > len)
 199                         avail = (unsigned long)len;
 200                 sha1write(f, in, avail);
 201                 offset += avail;
 202                 len -= avail;
 203         }
 204 }
 205
 206 /* Return 0 if we will bust the pack-size limit */
 207 static unsigned long write_object(struct sha1file *f,
 208                                   struct object_entry *entry,
 209                                   off_t write_offset)
 210 {
 211         unsigned long size, limit, datalen;
 212         void *buf;
 213         unsigned char header[10], dheader[10];
 214         unsigned hdrlen;
 215         enum object_type type;
 216         int usable_delta, to_reuse;
 217
 218         if (!pack_to_stdout)
 219                 crc32_begin(f);
 220
 221         type = entry->type;
 222
 223         /* apply size limit if limited packsize and not first object */
 224         if (!pack_size_limit || !nr_written)
 225                 limit = 0;
 226         else if (pack_size_limit <= write_offset)
 227                 /*
 228                  * the earlier object did not fit the limit; avoid
 229                  * mistaking this with unlimited (i.e. limit = 0).
 230                  */
 231                 limit = 1;
 232         else
 233                 limit = pack_size_limit - write_offset;
 234
 235         if (!entry->delta)
 236                 usable_delta = 0;       /* no delta */
 237         else if (!pack_size_limit)
 238                usable_delta = 1;        /* unlimited packfile */
 239         else if (entry->delta->idx.offset == (off_t)-1)
 240                 usable_delta = 0;       /* base was written to another pack */
 241         else if (entry->delta->idx.offset)
 242                 usable_delta = 1;       /* base already exists in this pack */
 243         else
 244                 usable_delta = 0;       /* base could end up in another pack */
 245
 246         if (!reuse_object)
 247                 to_reuse = 0;   /* explicit */
 248         else if (!entry->in_pack)
 249                 to_reuse = 0;   /* can't reuse what we don't have */
 250         else if (type == OBJ_REF_DELTA || type == OBJ_OFS_DELTA)
 251                                 /* check_object() decided it for us ... */
 252                 to_reuse = usable_delta;
 253                                 /* ... but pack split may override that */
 254         else if (type != entry->in_pack_type)
 255                 to_reuse = 0;   /* pack has delta which is unusable */
 256         else if (entry->delta)
 257                 to_reuse = 0;   /* we want to pack afresh */
 258         else
 259                 to_reuse = 1;   /* we have it in-pack undeltified,
 260                                  * and we do not need to deltify it.
 261                                  */
 262
 263         if (!to_reuse) {
 264                 no_reuse:
 265                 if (!usable_delta) {
 266                         buf = read_sha1_file(entry->idx.sha1, &type, &size);
 267                         if (!buf)
 268                                 die("unable to read %s", sha1_to_hex(entry->idx.sha1));
 269                         /*
 270                          * make sure no cached delta data remains from a
 271                          * previous attempt before a pack split occurred.
 272                          */
 273                         free(entry->delta_data);
 274                         entry->delta_data = NULL;
 275                         entry->z_delta_size = 0;
 276                 } else if (entry->delta_data) {
 277                         size = entry->delta_size;
 278                         buf = entry->delta_data;
 279                         entry->delta_data = NULL;
 280                         type = (allow_ofs_delta && entry->delta->idx.offset) ?
 281                                 OBJ_OFS_DELTA : OBJ_REF_DELTA;
 282                 } else {
 283                         buf = get_delta(entry);
 284                         size = entry->delta_size;
 285                         type = (allow_ofs_delta && entry->delta->idx.offset) ?
 286                                 OBJ_OFS_DELTA : OBJ_REF_DELTA;
 287                 }
 288
 289                 if (entry->z_delta_size)
 290                         datalen = entry->z_delta_size;
 291                 else
 292                         datalen = do_compress(&buf, size);
 293
 294                 /*
 295                  * The object header is a byte of 'type' followed by zero or
 296                  * more bytes of length.
 297                  */
 298                 hdrlen = encode_in_pack_object_header(type, size, header);
 299
 300                 if (type == OBJ_OFS_DELTA) {
 301                         /*
 302                          * Deltas with relative base contain an additional
 303                          * encoding of the relative offset for the delta
 304                          * base from this object's position in the pack.
 305                          */
 306                         off_t ofs = entry->idx.offset - entry->delta->idx.offset;
 307                         unsigned pos = sizeof(dheader) - 1;
 308                         dheader[pos] = ofs & 127;
 309                         while (ofs >>= 7)
 310                                 dheader[--pos] = 128 | (--ofs & 127);
 311                         if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
 312                                 free(buf);
 313                                 return 0;
 314                         }
 315                         sha1write(f, header, hdrlen);
 316                         sha1write(f, dheader + pos, sizeof(dheader) - pos);
 317                         hdrlen += sizeof(dheader) - pos;
 318                 } else if (type == OBJ_REF_DELTA) {
 319                         /*
 320                          * Deltas with a base reference contain
 321                          * an additional 20 bytes for the base sha1.
 322                          */
 323                         if (limit && hdrlen + 20 + datalen + 20 >= limit) {
 324                                 free(buf);
 325                                 return 0;
 326                         }
 327                         sha1write(f, header, hdrlen);
 328                         sha1write(f, entry->delta->idx.sha1, 20);
 329                         hdrlen += 20;
 330                 } else {
 331                         if (limit && hdrlen + datalen + 20 >= limit) {
 332                                 free(buf);
 333                                 return 0;
 334                         }
 335                         sha1write(f, header, hdrlen);
 336                 }
 337                 sha1write(f, buf, datalen);
 338                 free(buf);
 339         }
 340         else {
 341                 struct packed_git *p = entry->in_pack;
 342                 struct pack_window *w_curs = NULL;
 343                 struct revindex_entry *revidx;
 344                 off_t offset;
 345
 346                 if (entry->delta)
 347                         type = (allow_ofs_delta && entry->delta->idx.offset) ?
 348                                 OBJ_OFS_DELTA : OBJ_REF_DELTA;
 349                 hdrlen = encode_in_pack_object_header(type, entry->size, header);
 350
 351                 offset = entry->in_pack_offset;
 352                 revidx = find_pack_revindex(p, offset);
 353                 datalen = revidx[1].offset - offset;
 354                 if (!pack_to_stdout && p->index_version > 1 &&
 355                     check_pack_crc(p, &w_curs, offset, datalen, revidx->nr)) {
 356                         error("bad packed object CRC for %s", sha1_to_hex(entry->idx.sha1));
 357                         unuse_pack(&w_curs);
 358                         goto no_reuse;
 359                 }
 360
 361                 offset += entry->in_pack_header_size;
 362                 datalen -= entry->in_pack_header_size;
 363                 if (!pack_to_stdout && p->index_version == 1 &&
 364                     check_pack_inflate(p, &w_curs, offset, datalen, entry->size)) {
 365                         error("corrupt packed object for %s", sha1_to_hex(entry->idx.sha1));
 366                         unuse_pack(&w_curs);
 367                         goto no_reuse;
 368                 }
 369
 370                 if (type == OBJ_OFS_DELTA) {
 371                         off_t ofs = entry->idx.offset - entry->delta->idx.offset;
 372                         unsigned pos = sizeof(dheader) - 1;
 373                         dheader[pos] = ofs & 127;
 374                         while (ofs >>= 7)
 375                                 dheader[--pos] = 128 | (--ofs & 127);
 376                         if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
 377                                 unuse_pack(&w_curs);
 378                                 return 0;
 379                         }
 380                         sha1write(f, header, hdrlen);
 381                         sha1write(f, dheader + pos, sizeof(dheader) - pos);
 382                         hdrlen += sizeof(dheader) - pos;
 383                         reused_delta++;
 384                 } else if (type == OBJ_REF_DELTA) {
 385                         if (limit && hdrlen + 20 + datalen + 20 >= limit) {
 386                                 unuse_pack(&w_curs);
 387                                 return 0;
 388                         }
 389                         sha1write(f, header, hdrlen);
 390                         sha1write(f, entry->delta->idx.sha1, 20);
 391                         hdrlen += 20;
 392                         reused_delta++;
 393                 } else {
 394                         if (limit && hdrlen + datalen + 20 >= limit) {
 395                                 unuse_pack(&w_curs);
 396                                 return 0;
 397                         }
 398                         sha1write(f, header, hdrlen);
 399                 }
 400                 copy_pack_data(f, p, &w_curs, offset, datalen);
 401                 unuse_pack(&w_curs);
 402                 reused++;
 403         }
 404         if (usable_delta)
 405                 written_delta++;
 406         written++;
 407         if (!pack_to_stdout)
 408                 entry->idx.crc32 = crc32_end(f);
 409         return hdrlen + datalen;
 410 }
 411
 412 enum write_one_status {
 413         WRITE_ONE_SKIP = -1, /* already written */
 414         WRITE_ONE_BREAK = 0, /* writing this will bust the limit; not written */
 415         WRITE_ONE_WRITTEN = 1, /* normal */
 416         WRITE_ONE_RECURSIVE = 2 /* already scheduled to be written */
 417 };
 418
 419 static enum write_one_status write_one(struct sha1file *f,
 420                                        struct object_entry *e,
 421                                        off_t *offset)
 422 {
 423         unsigned long size;
 424         int recursing;
 425
 426         /*
 427          * we set offset to 1 (which is an impossible value) to mark
 428          * the fact that this object is involved in "write its base
 429          * first before writing a deltified object" recursion.
 430          */
 431         recursing = (e->idx.offset == 1);
 432         if (recursing) {
 433                 warning("recursive delta detected for object %s",
 434                         sha1_to_hex(e->idx.sha1));
 435                 return WRITE_ONE_RECURSIVE;
 436         } else if (e->idx.offset || e->preferred_base) {
 437                 /* offset is non zero if object is written already. */
 438                 return WRITE_ONE_SKIP;
 439         }
 440
 441         /* if we are deltified, write out base object first. */
 442         if (e->delta) {
 443                 e->idx.offset = 1; /* now recurse */
 444                 switch (write_one(f, e->delta, offset)) {
 445                 case WRITE_ONE_RECURSIVE:
 446                         /* we cannot depend on this one */
 447                         e->delta = NULL;
 448                         break;
 449                 default:
 450                         break;
 451                 case WRITE_ONE_BREAK:
 452                         e->idx.offset = recursing;
 453                         return WRITE_ONE_BREAK;
 454                 }
 455         }
 456
 457         e->idx.offset = *offset;
 458         size = write_object(f, e, *offset);
 459         if (!size) {
 460                 e->idx.offset = recursing;
 461                 return WRITE_ONE_BREAK;
 462         }
 463         written_list[nr_written++] = &e->idx;
 464
 465         /* make sure off_t is sufficiently large not to wrap */
 466         if (signed_add_overflows(*offset, size))
 467                 die("pack too large for current definition of off_t");
 468         *offset += size;
 469         return WRITE_ONE_WRITTEN;
 470 }
 471
 472 static int mark_tagged(const char *path, const unsigned char *sha1, int flag,
 473                        void *cb_data)
 474 {
 475         unsigned char peeled[20];
 476         struct object_entry *entry = locate_object_entry(sha1);
 477
 478         if (entry)
 479                 entry->tagged = 1;
 480         if (!peel_ref(path, peeled)) {
 481                 entry = locate_object_entry(peeled);
 482                 if (entry)
 483                         entry->tagged = 1;
 484         }
 485         return 0;
 486 }
 487
 488 static inline void add_to_write_order(struct object_entry **wo,
 489                                unsigned int *endp,
 490                                struct object_entry *e)
 491 {
 492         if (e->filled)
 493                 return;
 494         wo[(*endp)++] = e;
 495         e->filled = 1;
 496 }
 497
 498 static void add_descendants_to_write_order(struct object_entry **wo,
 499                                            unsigned int *endp,
 500                                            struct object_entry *e)
 501 {
 502         int add_to_order = 1;
 503         while (e) {
 504                 if (add_to_order) {
 505                         struct object_entry *s;
 506                         /* add this node... */
 507                         add_to_write_order(wo, endp, e);
 508                         /* all its siblings... */
 509                         for (s = e->delta_sibling; s; s = s->delta_sibling) {
 510                                 add_to_write_order(wo, endp, s);
 511                         }
 512                 }
 513                 /* drop down a level to add left subtree nodes if possible */
 514                 if (e->delta_child) {
 515                         add_to_order = 1;
 516                         e = e->delta_child;
 517                 } else {
 518                         add_to_order = 0;
 519                         /* our sibling might have some children, it is next */
 520                         if (e->delta_sibling) {
 521                                 e = e->delta_sibling;
 522                                 continue;
 523                         }
 524                         /* go back to our parent node */
 525                         e = e->delta;
 526                         while (e && !e->delta_sibling) {
 527                                 /* we're on the right side of a subtree, keep
 528                                  * going up until we can go right again */
 529                                 e = e->delta;
 530                         }
 531                         if (!e) {
 532                                 /* done- we hit our original root node */
 533                                 return;
 534                         }
 535                         /* pass it off to sibling at this level */
 536                         e = e->delta_sibling;
 537                 }
 538         };
 539 }
 540
 541 static void add_family_to_write_order(struct object_entry **wo,
 542                                       unsigned int *endp,
 543                                       struct object_entry *e)
 544 {
 545         struct object_entry *root;
 546
 547         for (root = e; root->delta; root = root->delta)
 548                 ; /* nothing */
 549         add_descendants_to_write_order(wo, endp, root);
 550 }
 551
 552 static struct object_entry **compute_write_order(void)
 553 {
 554         unsigned int i, wo_end, last_untagged;
 555
 556         struct object_entry **wo = xmalloc(nr_objects * sizeof(*wo));
 557
 558         for (i = 0; i < nr_objects; i++) {
 559                 objects[i].tagged = 0;
 560                 objects[i].filled = 0;
 561                 objects[i].delta_child = NULL;
 562                 objects[i].delta_sibling = NULL;
 563         }
 564
 565         /*
 566          * Fully connect delta_child/delta_sibling network.
 567          * Make sure delta_sibling is sorted in the original
 568          * recency order.
 569          */
 570         for (i = nr_objects; i > 0;) {
 571                 struct object_entry *e = &objects[--i];
 572                 if (!e->delta)
 573                         continue;
 574                 /* Mark me as the first child */
 575                 e->delta_sibling = e->delta->delta_child;
 576                 e->delta->delta_child = e;
 577         }
 578
 579         /*
 580          * Mark objects that are at the tip of tags.
 581          */
 582         for_each_tag_ref(mark_tagged, NULL);
 583
 584         /*
 585          * Give the objects in the original recency order until
 586          * we see a tagged tip.
 587          */
 588         for (i = wo_end = 0; i < nr_objects; i++) {
 589                 if (objects[i].tagged)
 590                         break;
 591                 add_to_write_order(wo, &wo_end, &objects[i]);
 592         }
 593         last_untagged = i;
 594
 595         /*
 596          * Then fill all the tagged tips.
 597          */
 598         for (; i < nr_objects; i++) {
 599                 if (objects[i].tagged)
 600                         add_to_write_order(wo, &wo_end, &objects[i]);
 601         }
 602
 603         /*
 604          * And then all remaining commits and tags.
 605          */
 606         for (i = last_untagged; i < nr_objects; i++) {
 607                 if (objects[i].type != OBJ_COMMIT &&
 608                     objects[i].type != OBJ_TAG)
 609                         continue;
 610                 add_to_write_order(wo, &wo_end, &objects[i]);
 611         }
 612
 613         /*
 614          * And then all the trees.
 615          */
 616         for (i = last_untagged; i < nr_objects; i++) {
 617                 if (objects[i].type != OBJ_TREE)
 618                         continue;
 619                 add_to_write_order(wo, &wo_end, &objects[i]);
 620         }
 621
 622         /*
 623          * Finally all the rest in really tight order
 624          */
 625         for (i = last_untagged; i < nr_objects; i++) {
 626                 if (!objects[i].filled)
 627                         add_family_to_write_order(wo, &wo_end, &objects[i]);
 628         }
 629
 630         if (wo_end != nr_objects)
 631                 die("ordered %u objects, expected %"PRIu32, wo_end, nr_objects);
 632
 633         return wo;
 634 }
 635
 636 static void write_pack_file(void)
 637 {
 638         uint32_t i = 0, j;
 639         struct sha1file *f;
 640         off_t offset;
 641         uint32_t nr_remaining = nr_result;
 642         time_t last_mtime = 0;
 643         struct object_entry **write_order;
 644
 645         if (progress > pack_to_stdout)
 646                 progress_state = start_progress("Writing objects", nr_result);
 647         written_list = xmalloc(nr_objects * sizeof(*written_list));
 648         write_order = compute_write_order();
 649
 650         do {
 651                 unsigned char sha1[20];
 652                 char *pack_tmp_name = NULL;
 653
 654                 if (pack_to_stdout)
 655                         f = sha1fd_throughput(1, "<stdout>", progress_state);
 656                 else
 657                         f = create_tmp_packfile(&pack_tmp_name);
 658
 659                 offset = write_pack_header(f, nr_remaining);
 660                 if (!offset)
 661                         die_errno("unable to write pack header");
 662                 nr_written = 0;
 663                 for (; i < nr_objects; i++) {
 664                         struct object_entry *e = write_order[i];
 665                         if (write_one(f, e, &offset) == WRITE_ONE_BREAK)
 666                                 break;
 667                         display_progress(progress_state, written);
 668                 }
 669
 670                 /*
 671                  * Did we write the wrong # entries in the header?
 672                  * If so, rewrite it like in fast-import
 673                  */
 674                 if (pack_to_stdout) {
 675                         sha1close(f, sha1, CSUM_CLOSE);
 676                 } else if (nr_written == nr_remaining) {
 677                         sha1close(f, sha1, CSUM_FSYNC);
 678                 } else {
 679                         int fd = sha1close(f, sha1, 0);
 680                         fixup_pack_header_footer(fd, sha1, pack_tmp_name,
 681                                                  nr_written, sha1, offset);
 682                         close(fd);
 683                 }
 684
 685                 if (!pack_to_stdout) {
 686                         struct stat st;
 687                         char tmpname[PATH_MAX];
 688
 689                         /*
 690                          * Packs are runtime accessed in their mtime
 691                          * order since newer packs are more likely to contain
 692                          * younger objects.  So if we are creating multiple
 693                          * packs then we should modify the mtime of later ones
 694                          * to preserve this property.
 695                          */
 696                         if (stat(pack_tmp_name, &st) < 0) {
 697                                 warning("failed to stat %s: %s",
 698                                         pack_tmp_name, strerror(errno));
 699                         } else if (!last_mtime) {
 700                                 last_mtime = st.st_mtime;
 701                         } else {
 702                                 struct utimbuf utb;
 703                                 utb.actime = st.st_atime;
 704                                 utb.modtime = --last_mtime;
 705                                 if (utime(pack_tmp_name, &utb) < 0)
 706                                         warning("failed utime() on %s: %s",
 707                                                 tmpname, strerror(errno));
 708                         }
 709
 710                         /* Enough space for "-<sha-1>.pack"? */
 711                         if (sizeof(tmpname) <= strlen(base_name) + 50)
 712                                 die("pack base name '%s' too long", base_name);
 713                         snprintf(tmpname, sizeof(tmpname), "%s-", base_name);
 714                         finish_tmp_packfile(tmpname, pack_tmp_name,
 715                                             written_list, nr_written,
 716                                             &pack_idx_opts, sha1);
 717                         free(pack_tmp_name);
 718                         puts(sha1_to_hex(sha1));
 719                 }
 720
 721                 /* mark written objects as written to previous pack */
 722                 for (j = 0; j < nr_written; j++) {
 723                         written_list[j]->offset = (off_t)-1;
 724                 }
 725                 nr_remaining -= nr_written;
 726         } while (nr_remaining && i < nr_objects);
 727
 728         free(written_list);
 729         free(write_order);
 730         stop_progress(&progress_state);
 731         if (written != nr_result)
 732                 die("wrote %"PRIu32" objects while expecting %"PRIu32,
 733                         written, nr_result);
 734 }
 735
 736 static int locate_object_entry_hash(const unsigned char *sha1)
 737 {
 738         int i;
 739         unsigned int ui;
 740         memcpy(&ui, sha1, sizeof(unsigned int));
 741         i = ui % object_ix_hashsz;
 742         while (0 < object_ix[i]) {
 743                 if (!hashcmp(sha1, objects[object_ix[i] - 1].idx.sha1))
 744                         return i;
 745                 if (++i == object_ix_hashsz)
 746                         i = 0;
 747         }
 748         return -1 - i;
 749 }
 750
 751 static struct object_entry *locate_object_entry(const unsigned char *sha1)
 752 {
 753         int i;
 754
 755         if (!object_ix_hashsz)
 756                 return NULL;
 757
 758         i = locate_object_entry_hash(sha1);
 759         if (0 <= i)
 760                 return &objects[object_ix[i]-1];
 761         return NULL;
 762 }
 763
 764 static void rehash_objects(void)
 765 {
 766         uint32_t i;
 767         struct object_entry *oe;
 768
 769         object_ix_hashsz = nr_objects * 3;
 770         if (object_ix_hashsz < 1024)
 771                 object_ix_hashsz = 1024;
 772         object_ix = xrealloc(object_ix, sizeof(int) * object_ix_hashsz);
 773         memset(object_ix, 0, sizeof(int) * object_ix_hashsz);
 774         for (i = 0, oe = objects; i < nr_objects; i++, oe++) {
 775                 int ix = locate_object_entry_hash(oe->idx.sha1);
 776                 if (0 <= ix)
 777                         continue;
 778                 ix = -1 - ix;
 779                 object_ix[ix] = i + 1;
 780         }
 781 }
 782
 783 static unsigned name_hash(const char *name)
 784 {
 785         unsigned c, hash = 0;
 786
 787         if (!name)
 788                 return 0;
 789
 790         /*
 791          * This effectively just creates a sortable number from the
 792          * last sixteen non-whitespace characters. Last characters
 793          * count "most", so things that end in ".c" sort together.
 794          */
 795         while ((c = *name++) != 0) {
 796                 if (isspace(c))
 797                         continue;
 798                 hash = (hash >> 2) + (c << 24);
 799         }
 800         return hash;
 801 }
 802
 803 static void setup_delta_attr_check(struct git_attr_check *check)
 804 {
 805         static struct git_attr *attr_delta;
 806
 807         if (!attr_delta)
 808                 attr_delta = git_attr("delta");
 809
 810         check[0].attr = attr_delta;
 811 }
 812
 813 static int no_try_delta(const char *path)
 814 {
 815         struct git_attr_check check[1];
 816
 817         setup_delta_attr_check(check);
 818         if (git_check_attr(path, ARRAY_SIZE(check), check))
 819                 return 0;
 820         if (ATTR_FALSE(check->value))
 821                 return 1;
 822         return 0;
 823 }
 824
 825 static int add_object_entry(const unsigned char *sha1, enum object_type type,
 826                             const char *name, int exclude)
 827 {
 828         struct object_entry *entry;
 829         struct packed_git *p, *found_pack = NULL;
 830         off_t found_offset = 0;
 831         int ix;
 832         unsigned hash = name_hash(name);
 833
 834         ix = nr_objects ? locate_object_entry_hash(sha1) : -1;
 835         if (ix >= 0) {
 836                 if (exclude) {
 837                         entry = objects + object_ix[ix] - 1;
 838                         if (!entry->preferred_base)
 839                                 nr_result--;
 840                         entry->preferred_base = 1;
 841                 }
 842                 return 0;
 843         }
 844
 845         if (!exclude && local && has_loose_object_nonlocal(sha1))
 846                 return 0;
 847
 848         for (p = packed_git; p; p = p->next) {
 849                 off_t offset = find_pack_entry_one(sha1, p);
 850                 if (offset) {
 851                         if (!found_pack) {
 852                                 if (!is_pack_valid(p)) {
 853                                         warning("packfile %s cannot be accessed", p->pack_name);
 854                                         continue;
 855                                 }
 856                                 found_offset = offset;
 857                                 found_pack = p;
 858                         }
 859                         if (exclude)
 860                                 break;
 861                         if (incremental)
 862                                 return 0;
 863                         if (local && !p->pack_local)
 864                                 return 0;
 865                         if (ignore_packed_keep && p->pack_local && p->pack_keep)
 866                                 return 0;
 867                 }
 868         }
 869
 870         if (nr_objects >= nr_alloc) {
 871                 nr_alloc = (nr_alloc  + 1024) * 3 / 2;
 872                 objects = xrealloc(objects, nr_alloc * sizeof(*entry));
 873         }
 874
 875         entry = objects + nr_objects++;
 876         memset(entry, 0, sizeof(*entry));
 877         hashcpy(entry->idx.sha1, sha1);
 878         entry->hash = hash;
 879         if (type)
 880                 entry->type = type;
 881         if (exclude)
 882                 entry->preferred_base = 1;
 883         else
 884                 nr_result++;
 885         if (found_pack) {
 886                 entry->in_pack = found_pack;
 887                 entry->in_pack_offset = found_offset;
 888         }
 889
 890         if (object_ix_hashsz * 3 <= nr_objects * 4)
 891                 rehash_objects();
 892         else
 893                 object_ix[-1 - ix] = nr_objects;
 894
 895         display_progress(progress_state, nr_objects);
 896
 897         if (name && no_try_delta(name))
 898                 entry->no_try_delta = 1;
 899
 900         return 1;
 901 }
 902
 903 struct pbase_tree_cache {
 904         unsigned char sha1[20];
 905         int ref;
 906         int temporary;
 907         void *tree_data;
 908         unsigned long tree_size;
 909 };
 910
 911 static struct pbase_tree_cache *(pbase_tree_cache[256]);
 912 static int pbase_tree_cache_ix(const unsigned char *sha1)
 913 {
 914         return sha1[0] % ARRAY_SIZE(pbase_tree_cache);
 915 }
 916 static int pbase_tree_cache_ix_incr(int ix)
 917 {
 918         return (ix+1) % ARRAY_SIZE(pbase_tree_cache);
 919 }
 920
 921 static struct pbase_tree {
 922         struct pbase_tree *next;
 923         /* This is a phony "cache" entry; we are not
 924          * going to evict it nor find it through _get()
 925          * mechanism -- this is for the toplevel node that
 926          * would almost always change with any commit.
 927          */
 928         struct pbase_tree_cache pcache;
 929 } *pbase_tree;
 930
 931 static struct pbase_tree_cache *pbase_tree_get(const unsigned char *sha1)
 932 {
 933         struct pbase_tree_cache *ent, *nent;
 934         void *data;
 935         unsigned long size;
 936         enum object_type type;
 937         int neigh;
 938         int my_ix = pbase_tree_cache_ix(sha1);
 939         int available_ix = -1;
 940
 941         /* pbase-tree-cache acts as a limited hashtable.
 942          * your object will be found at your index or within a few
 943          * slots after that slot if it is cached.
 944          */
 945         for (neigh = 0; neigh < 8; neigh++) {
 946                 ent = pbase_tree_cache[my_ix];
 947                 if (ent && !hashcmp(ent->sha1, sha1)) {
 948                         ent->ref++;
 949                         return ent;
 950                 }
 951                 else if (((available_ix < 0) && (!ent || !ent->ref)) ||
 952                          ((0 <= available_ix) &&
 953                           (!ent && pbase_tree_cache[available_ix])))
 954                         available_ix = my_ix;
 955                 if (!ent)
 956                         break;
 957                 my_ix = pbase_tree_cache_ix_incr(my_ix);
 958         }
 959
 960         /* Did not find one.  Either we got a bogus request or
 961          * we need to read and perhaps cache.
 962          */
 963         data = read_sha1_file(sha1, &type, &size);
 964         if (!data)
 965                 return NULL;
 966         if (type != OBJ_TREE) {
 967                 free(data);
 968                 return NULL;
 969         }
 970
 971         /* We need to either cache or return a throwaway copy */
 972
 973         if (available_ix < 0)
 974                 ent = NULL;
 975         else {
 976                 ent = pbase_tree_cache[available_ix];
 977                 my_ix = available_ix;
 978         }
 979
 980         if (!ent) {
 981                 nent = xmalloc(sizeof(*nent));
 982                 nent->temporary = (available_ix < 0);
 983         }
 984         else {
 985                 /* evict and reuse */
 986                 free(ent->tree_data);
 987                 nent = ent;
 988         }
 989         hashcpy(nent->sha1, sha1);
 990         nent->tree_data = data;
 991         nent->tree_size = size;
 992         nent->ref = 1;
 993         if (!nent->temporary)
 994                 pbase_tree_cache[my_ix] = nent;
 995         return nent;
 996 }
 997
 998 static void pbase_tree_put(struct pbase_tree_cache *cache)
 999 {
1000         if (!cache->temporary) {
1001                 cache->ref--;
1002                 return;
1003         }
1004         free(cache->tree_data);
1005         free(cache);
1006 }
1007
1008 static int name_cmp_len(const char *name)
1009 {
1010         int i;
1011         for (i = 0; name[i] && name[i] != '\n' && name[i] != '/'; i++)
1012                 ;
1013         return i;
1014 }
1015
1016 static void add_pbase_object(struct tree_desc *tree,
1017                              const char *name,
1018                              int cmplen,
1019                              const char *fullname)
1020 {
1021         struct name_entry entry;
1022         int cmp;
1023
1024         while (tree_entry(tree,&entry)) {
1025                 if (S_ISGITLINK(entry.mode))
1026                         continue;
1027                 cmp = tree_entry_len(&entry) != cmplen ? 1 :
1028                       memcmp(name, entry.path, cmplen);
1029                 if (cmp > 0)
1030                         continue;
1031                 if (cmp < 0)
1032                         return;
1033                 if (name[cmplen] != '/') {
1034                         add_object_entry(entry.sha1,
1035                                          object_type(entry.mode),
1036                                          fullname, 1);
1037                         return;
1038                 }
1039                 if (S_ISDIR(entry.mode)) {
1040                         struct tree_desc sub;
1041                         struct pbase_tree_cache *tree;
1042                         const char *down = name+cmplen+1;
1043                         int downlen = name_cmp_len(down);
1044
1045                         tree = pbase_tree_get(entry.sha1);
1046                         if (!tree)
1047                                 return;
1048                         init_tree_desc(&sub, tree->tree_data, tree->tree_size);
1049
1050                         add_pbase_object(&sub, down, downlen, fullname);
1051                         pbase_tree_put(tree);
1052                 }
1053         }
1054 }
1055
1056 static unsigned *done_pbase_paths;
1057 static int done_pbase_paths_num;
1058 static int done_pbase_paths_alloc;
1059 static int done_pbase_path_pos(unsigned hash)
1060 {
1061         int lo = 0;
1062         int hi = done_pbase_paths_num;
1063         while (lo < hi) {
1064                 int mi = (hi + lo) / 2;
1065                 if (done_pbase_paths[mi] == hash)
1066                         return mi;
1067                 if (done_pbase_paths[mi] < hash)
1068                         hi = mi;
1069                 else
1070                         lo = mi + 1;
1071         }
1072         return -lo-1;
1073 }
1074
1075 static int check_pbase_path(unsigned hash)
1076 {
1077         int pos = (!done_pbase_paths) ? -1 : done_pbase_path_pos(hash);
1078         if (0 <= pos)
1079                 return 1;
1080         pos = -pos - 1;
1081         if (done_pbase_paths_alloc <= done_pbase_paths_num) {
1082                 done_pbase_paths_alloc = alloc_nr(done_pbase_paths_alloc);
1083                 done_pbase_paths = xrealloc(done_pbase_paths,
1084                                             done_pbase_paths_alloc *
1085                                             sizeof(unsigned));
1086         }
1087         done_pbase_paths_num++;
1088         if (pos < done_pbase_paths_num)
1089                 memmove(done_pbase_paths + pos + 1,
1090                         done_pbase_paths + pos,
1091                         (done_pbase_paths_num - pos - 1) * sizeof(unsigned));
1092         done_pbase_paths[pos] = hash;
1093         return 0;
1094 }
1095
1096 static void add_preferred_base_object(const char *name)
1097 {
1098         struct pbase_tree *it;
1099         int cmplen;
1100         unsigned hash = name_hash(name);
1101
1102         if (!num_preferred_base || check_pbase_path(hash))
1103                 return;
1104
1105         cmplen = name_cmp_len(name);
1106         for (it = pbase_tree; it; it = it->next) {
1107                 if (cmplen == 0) {
1108                         add_object_entry(it->pcache.sha1, OBJ_TREE, NULL, 1);
1109                 }
1110                 else {
1111                         struct tree_desc tree;
1112                         init_tree_desc(&tree, it->pcache.tree_data, it->pcache.tree_size);
1113                         add_pbase_object(&tree, name, cmplen, name);
1114                 }
1115         }
1116 }
1117
1118 static void add_preferred_base(unsigned char *sha1)
1119 {
1120         struct pbase_tree *it;
1121         void *data;
1122         unsigned long size;
1123         unsigned char tree_sha1[20];
1124
1125         if (window <= num_preferred_base++)
1126                 return;
1127
1128         data = read_object_with_reference(sha1, tree_type, &size, tree_sha1);
1129         if (!data)
1130                 return;
1131
1132         for (it = pbase_tree; it; it = it->next) {
1133                 if (!hashcmp(it->pcache.sha1, tree_sha1)) {
1134                         free(data);
1135                         return;
1136                 }
1137         }
1138
1139         it = xcalloc(1, sizeof(*it));
1140         it->next = pbase_tree;
1141         pbase_tree = it;
1142
1143         hashcpy(it->pcache.sha1, tree_sha1);
1144         it->pcache.tree_data = data;
1145         it->pcache.tree_size = size;
1146 }
1147
1148 static void cleanup_preferred_base(void)
1149 {
1150         struct pbase_tree *it;
1151         unsigned i;
1152
1153         it = pbase_tree;
1154         pbase_tree = NULL;
1155         while (it) {
1156                 struct pbase_tree *this = it;
1157                 it = this->next;
1158                 free(this->pcache.tree_data);
1159                 free(this);
1160         }
1161
1162         for (i = 0; i < ARRAY_SIZE(pbase_tree_cache); i++) {
1163                 if (!pbase_tree_cache[i])
1164                         continue;
1165                 free(pbase_tree_cache[i]->tree_data);
1166                 free(pbase_tree_cache[i]);
1167                 pbase_tree_cache[i] = NULL;
1168         }
1169
1170         free(done_pbase_paths);
1171         done_pbase_paths = NULL;
1172         done_pbase_paths_num = done_pbase_paths_alloc = 0;
1173 }
1174
1175 static void check_object(struct object_entry *entry)
1176 {
1177         if (entry->in_pack) {
1178                 struct packed_git *p = entry->in_pack;
1179                 struct pack_window *w_curs = NULL;
1180                 const unsigned char *base_ref = NULL;
1181                 struct object_entry *base_entry;
1182                 unsigned long used, used_0;
1183                 unsigned long avail;
1184                 off_t ofs;
1185                 unsigned char *buf, c;
1186
1187                 buf = use_pack(p, &w_curs, entry->in_pack_offset, &avail);
1188
1189                 /*
1190                  * We want in_pack_type even if we do not reuse delta
1191                  * since non-delta representations could still be reused.
1192                  */
1193                 used = unpack_object_header_buffer(buf, avail,
1194                                                    &entry->in_pack_type,
1195                                                    &entry->size);
1196                 if (used == 0)
1197                         goto give_up;
1198
1199                 /*
1200                  * Determine if this is a delta and if so whether we can
1201                  * reuse it or not.  Otherwise let's find out as cheaply as
1202                  * possible what the actual type and size for this object is.
1203                  */
1204                 switch (entry->in_pack_type) {
1205                 default:
1206                         /* Not a delta hence we've already got all we need. */
1207                         entry->type = entry->in_pack_type;
1208                         entry->in_pack_header_size = used;
1209                         if (entry->type < OBJ_COMMIT || entry->type > OBJ_BLOB)
1210                                 goto give_up;
1211                         unuse_pack(&w_curs);
1212                         return;
1213                 case OBJ_REF_DELTA:
1214                         if (reuse_delta && !entry->preferred_base)
1215                                 base_ref = use_pack(p, &w_curs,
1216                                                 entry->in_pack_offset + used, NULL);
1217                         entry->in_pack_header_size = used + 20;
1218                         break;
1219                 case OBJ_OFS_DELTA:
1220                         buf = use_pack(p, &w_curs,
1221                                        entry->in_pack_offset + used, NULL);
1222                         used_0 = 0;
1223                         c = buf[used_0++];
1224                         ofs = c & 127;
1225                         while (c & 128) {
1226                                 ofs += 1;
1227                                 if (!ofs || MSB(ofs, 7)) {
1228                                         error("delta base offset overflow in pack for %s",
1229                                               sha1_to_hex(entry->idx.sha1));
1230                                         goto give_up;
1231                                 }
1232                                 c = buf[used_0++];
1233                                 ofs = (ofs << 7) + (c & 127);
1234                         }
1235                         ofs = entry->in_pack_offset - ofs;
1236                         if (ofs <= 0 || ofs >= entry->in_pack_offset) {
1237                                 error("delta base offset out of bound for %s",
1238                                       sha1_to_hex(entry->idx.sha1));
1239                                 goto give_up;
1240                         }
1241                         if (reuse_delta && !entry->preferred_base) {
1242                                 struct revindex_entry *revidx;
1243                                 revidx = find_pack_revindex(p, ofs);
1244                                 if (!revidx)
1245                                         goto give_up;
1246                                 base_ref = nth_packed_object_sha1(p, revidx->nr);
1247                         }
1248                         entry->in_pack_header_size = used + used_0;
1249                         break;
1250                 }
1251
1252                 if (base_ref && (base_entry = locate_object_entry(base_ref))) {
1253                         /*
1254                          * If base_ref was set above that means we wish to
1255                          * reuse delta data, and we even found that base
1256                          * in the list of objects we want to pack. Goodie!
1257                          *
1258                          * Depth value does not matter - find_deltas() will
1259                          * never consider reused delta as the base object to
1260                          * deltify other objects against, in order to avoid
1261                          * circular deltas.
1262                          */
1263                         entry->type = entry->in_pack_type;
1264                         entry->delta = base_entry;
1265                         entry->delta_size = entry->size;
1266                         entry->delta_sibling = base_entry->delta_child;
1267                         base_entry->delta_child = entry;
1268                         unuse_pack(&w_curs);
1269                         return;
1270                 }
1271
1272                 if (entry->type) {
1273                         /*
1274                          * This must be a delta and we already know what the
1275                          * final object type is.  Let's extract the actual
1276                          * object size from the delta header.
1277                          */
1278                         entry->size = get_size_from_delta(p, &w_curs,
1279                                         entry->in_pack_offset + entry->in_pack_header_size);
1280                         if (entry->size == 0)
1281                                 goto give_up;
1282                         unuse_pack(&w_curs);
1283                         return;
1284                 }
1285
1286                 /*
1287                  * No choice but to fall back to the recursive delta walk
1288                  * with sha1_object_info() to find about the object type
1289                  * at this point...
1290                  */
1291                 give_up:
1292                 unuse_pack(&w_curs);
1293         }
1294
1295         entry->type = sha1_object_info(entry->idx.sha1, &entry->size);
1296         /*
1297          * The error condition is checked in prepare_pack().  This is
1298          * to permit a missing preferred base object to be ignored
1299          * as a preferred base.  Doing so can result in a larger
1300          * pack file, but the transfer will still take place.
1301          */
1302 }
1303
1304 static int pack_offset_sort(const void *_a, const void *_b)
1305 {
1306         const struct object_entry *a = *(struct object_entry **)_a;
1307         const struct object_entry *b = *(struct object_entry **)_b;
1308
1309         /* avoid filesystem trashing with loose objects */
1310         if (!a->in_pack && !b->in_pack)
1311                 return hashcmp(a->idx.sha1, b->idx.sha1);
1312
1313         if (a->in_pack < b->in_pack)
1314                 return -1;
1315         if (a->in_pack > b->in_pack)
1316                 return 1;
1317         return a->in_pack_offset < b->in_pack_offset ? -1 :
1318                         (a->in_pack_offset > b->in_pack_offset);
1319 }
1320
1321 static void get_object_details(void)
1322 {
1323         uint32_t i;
1324         struct object_entry **sorted_by_offset;
1325
1326         sorted_by_offset = xcalloc(nr_objects, sizeof(struct object_entry *));
1327         for (i = 0; i < nr_objects; i++)
1328                 sorted_by_offset[i] = objects + i;
1329         qsort(sorted_by_offset, nr_objects, sizeof(*sorted_by_offset), pack_offset_sort);
1330
1331         for (i = 0; i < nr_objects; i++) {
1332                 struct object_entry *entry = sorted_by_offset[i];
1333                 check_object(entry);
1334                 if (big_file_threshold <= entry->size)
1335                         entry->no_try_delta = 1;
1336         }
1337
1338         free(sorted_by_offset);
1339 }
1340
1341 /*
1342  * We search for deltas in a list sorted by type, by filename hash, and then
1343  * by size, so that we see progressively smaller and smaller files.
1344  * That's because we prefer deltas to be from the bigger file
1345  * to the smaller -- deletes are potentially cheaper, but perhaps
1346  * more importantly, the bigger file is likely the more recent
1347  * one.  The deepest deltas are therefore the oldest objects which are
1348  * less susceptible to be accessed often.
1349  */
1350 static int type_size_sort(const void *_a, const void *_b)
1351 {
1352         const struct object_entry *a = *(struct object_entry **)_a;
1353         const struct object_entry *b = *(struct object_entry **)_b;
1354
1355         if (a->type > b->type)
1356                 return -1;
1357         if (a->type < b->type)
1358                 return 1;
1359         if (a->hash > b->hash)
1360                 return -1;
1361         if (a->hash < b->hash)
1362                 return 1;
1363         if (a->preferred_base > b->preferred_base)
1364                 return -1;
1365         if (a->preferred_base < b->preferred_base)
1366                 return 1;
1367         if (a->size > b->size)
1368                 return -1;
1369         if (a->size < b->size)
1370                 return 1;
1371         return a < b ? -1 : (a > b);  /* newest first */
1372 }
1373
1374 struct unpacked {
1375         struct object_entry *entry;
1376         void *data;
1377         struct delta_index *index;
1378         unsigned depth;
1379 };
1380
1381 static int delta_cacheable(unsigned long src_size, unsigned long trg_size,
1382                            unsigned long delta_size)
1383 {
1384         if (max_delta_cache_size && delta_cache_size + delta_size > max_delta_cache_size)
1385                 return 0;
1386
1387         if (delta_size < cache_max_small_delta_size)
1388                 return 1;
1389
1390         /* cache delta, if objects are large enough compared to delta size */
1391         if ((src_size >> 20) + (trg_size >> 21) > (delta_size >> 10))
1392                 return 1;
1393
1394         return 0;
1395 }
1396
1397 #ifndef NO_PTHREADS
1398
1399 static pthread_mutex_t read_mutex;
1400 #define read_lock()             pthread_mutex_lock(&read_mutex)
1401 #define read_unlock()           pthread_mutex_unlock(&read_mutex)
1402
1403 static pthread_mutex_t cache_mutex;
1404 #define cache_lock()            pthread_mutex_lock(&cache_mutex)
1405 #define cache_unlock()          pthread_mutex_unlock(&cache_mutex)
1406
1407 static pthread_mutex_t progress_mutex;
1408 #define progress_lock()         pthread_mutex_lock(&progress_mutex)
1409 #define progress_unlock()       pthread_mutex_unlock(&progress_mutex)
1410
1411 #else
1412
1413 #define read_lock()             (void)0
1414 #define read_unlock()           (void)0
1415 #define cache_lock()            (void)0
1416 #define cache_unlock()          (void)0
1417 #define progress_lock()         (void)0
1418 #define progress_unlock()       (void)0
1419
1420 #endif
1421
1422 static int try_delta(struct unpacked *trg, struct unpacked *src,
1423                      unsigned max_depth, unsigned long *mem_usage)
1424 {
1425         struct object_entry *trg_entry = trg->entry;
1426         struct object_entry *src_entry = src->entry;
1427         unsigned long trg_size, src_size, delta_size, sizediff, max_size, sz;
1428         unsigned ref_depth;
1429         enum object_type type;
1430         void *delta_buf;
1431
1432         /* Don't bother doing diffs between different types */
1433         if (trg_entry->type != src_entry->type)
1434                 return -1;
1435
1436         /*
1437          * We do not bother to try a delta that we discarded on an
1438          * earlier try, but only when reusing delta data.  Note that
1439          * src_entry that is marked as the preferred_base should always
1440          * be considered, as even if we produce a suboptimal delta against
1441          * it, we will still save the transfer cost, as we already know
1442          * the other side has it and we won't send src_entry at all.
1443          */
1444         if (reuse_delta && trg_entry->in_pack &&
1445             trg_entry->in_pack == src_entry->in_pack &&
1446             !src_entry->preferred_base &&
1447             trg_entry->in_pack_type != OBJ_REF_DELTA &&
1448             trg_entry->in_pack_type != OBJ_OFS_DELTA)
1449                 return 0;
1450
1451         /* Let's not bust the allowed depth. */
1452         if (src->depth >= max_depth)
1453                 return 0;
1454
1455         /* Now some size filtering heuristics. */
1456         trg_size = trg_entry->size;
1457         if (!trg_entry->delta) {
1458                 max_size = trg_size/2 - 20;
1459                 ref_depth = 1;
1460         } else {
1461                 max_size = trg_entry->delta_size;
1462                 ref_depth = trg->depth;
1463         }
1464         max_size = (uint64_t)max_size * (max_depth - src->depth) /
1465                                                 (max_depth - ref_depth + 1);
1466         if (max_size == 0)
1467                 return 0;
1468         src_size = src_entry->size;
1469         sizediff = src_size < trg_size ? trg_size - src_size : 0;
1470         if (sizediff >= max_size)
1471                 return 0;
1472         if (trg_size < src_size / 32)
1473                 return 0;
1474
1475         /* Load data if not already done */
1476         if (!trg->data) {
1477                 read_lock();
1478                 trg->data = read_sha1_file(trg_entry->idx.sha1, &type, &sz);
1479                 read_unlock();
1480                 if (!trg->data)
1481                         die("object %s cannot be read",
1482                             sha1_to_hex(trg_entry->idx.sha1));
1483                 if (sz != trg_size)
1484                         die("object %s inconsistent object length (%lu vs %lu)",
1485                             sha1_to_hex(trg_entry->idx.sha1), sz, trg_size);
1486                 *mem_usage += sz;
1487         }
1488         if (!src->data) {
1489                 read_lock();
1490                 src->data = read_sha1_file(src_entry->idx.sha1, &type, &sz);
1491                 read_unlock();
1492                 if (!src->data) {
1493                         if (src_entry->preferred_base) {
1494                                 static int warned = 0;
1495                                 if (!warned++)
1496                                         warning("object %s cannot be read",
1497                                                 sha1_to_hex(src_entry->idx.sha1));
1498                                 /*
1499                                  * Those objects are not included in the
1500                                  * resulting pack.  Be resilient and ignore
1501                                  * them if they can't be read, in case the
1502                                  * pack could be created nevertheless.
1503                                  */
1504                                 return 0;
1505                         }
1506                         die("object %s cannot be read",
1507                             sha1_to_hex(src_entry->idx.sha1));
1508                 }
1509                 if (sz != src_size)
1510                         die("object %s inconsistent object length (%lu vs %lu)",
1511                             sha1_to_hex(src_entry->idx.sha1), sz, src_size);
1512                 *mem_usage += sz;
1513         }
1514         if (!src->index) {
1515                 src->index = create_delta_index(src->data, src_size);
1516                 if (!src->index) {
1517                         static int warned = 0;
1518                         if (!warned++)
1519                                 warning("suboptimal pack - out of memory");
1520                         return 0;
1521                 }
1522                 *mem_usage += sizeof_delta_index(src->index);
1523         }
1524
1525         delta_buf = create_delta(src->index, trg->data, trg_size, &delta_size, max_size);
1526         if (!delta_buf)
1527                 return 0;
1528
1529         if (trg_entry->delta) {
1530                 /* Prefer only shallower same-sized deltas. */
1531                 if (delta_size == trg_entry->delta_size &&
1532                     src->depth + 1 >= trg->depth) {
1533                         free(delta_buf);
1534                         return 0;
1535                 }
1536         }
1537
1538         /*
1539          * Handle memory allocation outside of the cache
1540          * accounting lock.  Compiler will optimize the strangeness
1541          * away when NO_PTHREADS is defined.
1542          */
1543         free(trg_entry->delta_data);
1544         cache_lock();
1545         if (trg_entry->delta_data) {
1546                 delta_cache_size -= trg_entry->delta_size;
1547                 trg_entry->delta_data = NULL;
1548         }
1549         if (delta_cacheable(src_size, trg_size, delta_size)) {
1550                 delta_cache_size += delta_size;
1551                 cache_unlock();
1552                 trg_entry->delta_data = xrealloc(delta_buf, delta_size);
1553         } else {
1554                 cache_unlock();
1555                 free(delta_buf);
1556         }
1557
1558         trg_entry->delta = src_entry;
1559         trg_entry->delta_size = delta_size;
1560         trg->depth = src->depth + 1;
1561
1562         return 1;
1563 }
1564
1565 static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
1566 {
1567         struct object_entry *child = me->delta_child;
1568         unsigned int m = n;
1569         while (child) {
1570                 unsigned int c = check_delta_limit(child, n + 1);
1571                 if (m < c)
1572                         m = c;
1573                 child = child->delta_sibling;
1574         }
1575         return m;
1576 }
1577
1578 static unsigned long free_unpacked(struct unpacked *n)
1579 {
1580         unsigned long freed_mem = sizeof_delta_index(n->index);
1581         free_delta_index(n->index);
1582         n->index = NULL;
1583         if (n->data) {
1584                 freed_mem += n->entry->size;
1585                 free(n->data);
1586                 n->data = NULL;
1587         }
1588         n->entry = NULL;
1589         n->depth = 0;
1590         return freed_mem;
1591 }
1592
1593 static void find_deltas(struct object_entry **list, unsigned *list_size,
1594                         int window, int depth, unsigned *processed)
1595 {
1596         uint32_t i, idx = 0, count = 0;
1597         struct unpacked *array;
1598         unsigned long mem_usage = 0;
1599
1600         array = xcalloc(window, sizeof(struct unpacked));
1601
1602         for (;;) {
1603                 struct object_entry *entry;
1604                 struct unpacked *n = array + idx;
1605                 int j, max_depth, best_base = -1;
1606
1607                 progress_lock();
1608                 if (!*list_size) {
1609                         progress_unlock();
1610                         break;
1611                 }
1612                 entry = *list++;
1613                 (*list_size)--;
1614                 if (!entry->preferred_base) {
1615                         (*processed)++;
1616                         display_progress(progress_state, *processed);
1617                 }
1618                 progress_unlock();
1619
1620                 mem_usage -= free_unpacked(n);
1621                 n->entry = entry;
1622
1623                 while (window_memory_limit &&
1624                        mem_usage > window_memory_limit &&
1625                        count > 1) {
1626                         uint32_t tail = (idx + window - count) % window;
1627                         mem_usage -= free_unpacked(array + tail);
1628                         count--;
1629                 }
1630
1631                 /* We do not compute delta to *create* objects we are not
1632                  * going to pack.
1633                  */
1634                 if (entry->preferred_base)
1635                         goto next;
1636
1637                 /*
1638                  * If the current object is at pack edge, take the depth the
1639                  * objects that depend on the current object into account
1640                  * otherwise they would become too deep.
1641                  */
1642                 max_depth = depth;
1643                 if (entry->delta_child) {
1644                         max_depth -= check_delta_limit(entry, 0);
1645                         if (max_depth <= 0)
1646                                 goto next;
1647                 }
1648
1649                 j = window;
1650                 while (--j > 0) {
1651                         int ret;
1652                         uint32_t other_idx = idx + j;
1653                         struct unpacked *m;
1654                         if (other_idx >= window)
1655                                 other_idx -= window;
1656                         m = array + other_idx;
1657                         if (!m->entry)
1658                                 break;
1659                         ret = try_delta(n, m, max_depth, &mem_usage);
1660                         if (ret < 0)
1661                                 break;
1662                         else if (ret > 0)
1663                                 best_base = other_idx;
1664                 }
1665
1666                 /*
1667                  * If we decided to cache the delta data, then it is best
1668                  * to compress it right away.  First because we have to do
1669                  * it anyway, and doing it here while we're threaded will
1670                  * save a lot of time in the non threaded write phase,
1671                  * as well as allow for caching more deltas within
1672                  * the same cache size limit.
1673                  * ...
1674                  * But only if not writing to stdout, since in that case
1675                  * the network is most likely throttling writes anyway,
1676                  * and therefore it is best to go to the write phase ASAP
1677                  * instead, as we can afford spending more time compressing
1678                  * between writes at that moment.
1679                  */
1680                 if (entry->delta_data && !pack_to_stdout) {
1681                         entry->z_delta_size = do_compress(&entry->delta_data,
1682                                                           entry->delta_size);
1683                         cache_lock();
1684                         delta_cache_size -= entry->delta_size;
1685                         delta_cache_size += entry->z_delta_size;
1686                         cache_unlock();
1687                 }
1688
1689                 /* if we made n a delta, and if n is already at max
1690                  * depth, leaving it in the window is pointless.  we
1691                  * should evict it first.
1692                  */
1693                 if (entry->delta && max_depth <= n->depth)
1694                         continue;
1695
1696                 /*
1697                  * Move the best delta base up in the window, after the
1698                  * currently deltified object, to keep it longer.  It will
1699                  * be the first base object to be attempted next.
1700                  */
1701                 if (entry->delta) {
1702                         struct unpacked swap = array[best_base];
1703                         int dist = (window + idx - best_base) % window;
1704                         int dst = best_base;
1705                         while (dist--) {
1706                                 int src = (dst + 1) % window;
1707                                 array[dst] = array[src];
1708                                 dst = src;
1709                         }
1710                         array[dst] = swap;
1711                 }
1712
1713                 next:
1714                 idx++;
1715                 if (count + 1 < window)
1716                         count++;
1717                 if (idx >= window)
1718                         idx = 0;
1719         }
1720
1721         for (i = 0; i < window; ++i) {
1722                 free_delta_index(array[i].index);
1723                 free(array[i].data);
1724         }
1725         free(array);
1726 }
1727
1728 #ifndef NO_PTHREADS
1729
1730 static void try_to_free_from_threads(size_t size)
1731 {
1732         read_lock();
1733         release_pack_memory(size, -1);
1734         read_unlock();
1735 }
1736
1737 static try_to_free_t old_try_to_free_routine;
1738
1739 /*
1740  * The main thread waits on the condition that (at least) one of the workers
1741  * has stopped working (which is indicated in the .working member of
1742  * struct thread_params).
1743  * When a work thread has completed its work, it sets .working to 0 and
1744  * signals the main thread and waits on the condition that .data_ready
1745  * becomes 1.
1746  */
1747
1748 struct thread_params {
1749         pthread_t thread;
1750         struct object_entry **list;
1751         unsigned list_size;
1752         unsigned remaining;
1753         int window;
1754         int depth;
1755         int working;
1756         int data_ready;
1757         pthread_mutex_t mutex;
1758         pthread_cond_t cond;
1759         unsigned *processed;
1760 };
1761
1762 static pthread_cond_t progress_cond;
1763
1764 /*
1765  * Mutex and conditional variable can't be statically-initialized on Windows.
1766  */
1767 static void init_threaded_search(void)
1768 {
1769         init_recursive_mutex(&read_mutex);
1770         pthread_mutex_init(&cache_mutex, NULL);
1771         pthread_mutex_init(&progress_mutex, NULL);
1772         pthread_cond_init(&progress_cond, NULL);
1773         old_try_to_free_routine = set_try_to_free_routine(try_to_free_from_threads);
1774 }
1775
1776 static void cleanup_threaded_search(void)
1777 {
1778         set_try_to_free_routine(old_try_to_free_routine);
1779         pthread_cond_destroy(&progress_cond);
1780         pthread_mutex_destroy(&read_mutex);
1781         pthread_mutex_destroy(&cache_mutex);
1782         pthread_mutex_destroy(&progress_mutex);
1783 }
1784
1785 static void *threaded_find_deltas(void *arg)
1786 {
1787         struct thread_params *me = arg;
1788
1789         while (me->remaining) {
1790                 find_deltas(me->list, &me->remaining,
1791                             me->window, me->depth, me->processed);
1792
1793                 progress_lock();
1794                 me->working = 0;
1795                 pthread_cond_signal(&progress_cond);
1796                 progress_unlock();
1797
1798                 /*
1799                  * We must not set ->data_ready before we wait on the
1800                  * condition because the main thread may have set it to 1
1801                  * before we get here. In order to be sure that new
1802                  * work is available if we see 1 in ->data_ready, it
1803                  * was initialized to 0 before this thread was spawned
1804                  * and we reset it to 0 right away.
1805                  */
1806                 pthread_mutex_lock(&me->mutex);
1807                 while (!me->data_ready)
1808                         pthread_cond_wait(&me->cond, &me->mutex);
1809                 me->data_ready = 0;
1810                 pthread_mutex_unlock(&me->mutex);
1811         }
1812         /* leave ->working 1 so that this doesn't get more work assigned */
1813         return NULL;
1814 }
1815
1816 static void ll_find_deltas(struct object_entry **list, unsigned list_size,
1817                            int window, int depth, unsigned *processed)
1818 {
1819         struct thread_params *p;
1820         int i, ret, active_threads = 0;
1821
1822         init_threaded_search();
1823
1824         if (!delta_search_threads)      /* --threads=0 means autodetect */
1825                 delta_search_threads = online_cpus();
1826         if (delta_search_threads <= 1) {
1827                 find_deltas(list, &list_size, window, depth, processed);
1828                 cleanup_threaded_search();
1829                 return;
1830         }
1831         if (progress > pack_to_stdout)
1832                 fprintf(stderr, "Delta compression using up to %d threads.\n",
1833                                 delta_search_threads);
1834         p = xcalloc(delta_search_threads, sizeof(*p));
1835
1836         /* Partition the work amongst work threads. */
1837         for (i = 0; i < delta_search_threads; i++) {
1838                 unsigned sub_size = list_size / (delta_search_threads - i);
1839
1840                 /* don't use too small segments or no deltas will be found */
1841                 if (sub_size < 2*window && i+1 < delta_search_threads)
1842                         sub_size = 0;
1843
1844                 p[i].window = window;
1845                 p[i].depth = depth;
1846                 p[i].processed = processed;
1847                 p[i].working = 1;
1848                 p[i].data_ready = 0;
1849
1850                 /* try to split chunks on "path" boundaries */
1851                 while (sub_size && sub_size < list_size &&
1852                        list[sub_size]->hash &&
1853                        list[sub_size]->hash == list[sub_size-1]->hash)
1854                         sub_size++;
1855
1856                 p[i].list = list;
1857                 p[i].list_size = sub_size;
1858                 p[i].remaining = sub_size;
1859
1860                 list += sub_size;
1861                 list_size -= sub_size;
1862         }
1863
1864         /* Start work threads. */
1865         for (i = 0; i < delta_search_threads; i++) {
1866                 if (!p[i].list_size)
1867                         continue;
1868                 pthread_mutex_init(&p[i].mutex, NULL);
1869                 pthread_cond_init(&p[i].cond, NULL);
1870                 ret = pthread_create(&p[i].thread, NULL,
1871                                      threaded_find_deltas, &p[i]);
1872                 if (ret)
1873                         die("unable to create thread: %s", strerror(ret));
1874                 active_threads++;
1875         }
1876
1877         /*
1878          * Now let's wait for work completion.  Each time a thread is done
1879          * with its work, we steal half of the remaining work from the
1880          * thread with the largest number of unprocessed objects and give
1881          * it to that newly idle thread.  This ensure good load balancing
1882          * until the remaining object list segments are simply too short
1883          * to be worth splitting anymore.
1884          */
1885         while (active_threads) {
1886                 struct thread_params *target = NULL;
1887                 struct thread_params *victim = NULL;
1888                 unsigned sub_size = 0;
1889
1890                 progress_lock();
1891                 for (;;) {
1892                         for (i = 0; !target && i < delta_search_threads; i++)
1893                                 if (!p[i].working)
1894                                         target = &p[i];
1895                         if (target)
1896                                 break;
1897                         pthread_cond_wait(&progress_cond, &progress_mutex);
1898                 }
1899
1900                 for (i = 0; i < delta_search_threads; i++)
1901                         if (p[i].remaining > 2*window &&
1902                             (!victim || victim->remaining < p[i].remaining))
1903                                 victim = &p[i];
1904                 if (victim) {
1905                         sub_size = victim->remaining / 2;
1906                         list = victim->list + victim->list_size - sub_size;
1907                         while (sub_size && list[0]->hash &&
1908                                list[0]->hash == list[-1]->hash) {
1909                                 list++;
1910                                 sub_size--;
1911                         }
1912                         if (!sub_size) {
1913                                 /*
1914                                  * It is possible for some "paths" to have
1915                                  * so many objects that no hash boundary
1916                                  * might be found.  Let's just steal the
1917                                  * exact half in that case.
1918                                  */
1919                                 sub_size = victim->remaining / 2;
1920                                 list -= sub_size;
1921                         }
1922                         target->list = list;
1923                         victim->list_size -= sub_size;
1924                         victim->remaining -= sub_size;
1925                 }
1926                 target->list_size = sub_size;
1927                 target->remaining = sub_size;
1928                 target->working = 1;
1929                 progress_unlock();
1930
1931                 pthread_mutex_lock(&target->mutex);
1932                 target->data_ready = 1;
1933                 pthread_cond_signal(&target->cond);
1934                 pthread_mutex_unlock(&target->mutex);
1935
1936                 if (!sub_size) {
1937                         pthread_join(target->thread, NULL);
1938                         pthread_cond_destroy(&target->cond);
1939                         pthread_mutex_destroy(&target->mutex);
1940                         active_threads--;
1941                 }
1942         }
1943         cleanup_threaded_search();
1944         free(p);
1945 }
1946
1947 #else
1948 #define ll_find_deltas(l, s, w, d, p)   find_deltas(l, &s, w, d, p)
1949 #endif
1950
1951 static int add_ref_tag(const char *path, const unsigned char *sha1, int flag, void *cb_data)
1952 {
1953         unsigned char peeled[20];
1954
1955         if (!prefixcmp(path, "refs/tags/") && /* is a tag? */
1956             !peel_ref(path, peeled)        && /* peelable? */
1957             !is_null_sha1(peeled)          && /* annotated tag? */
1958             locate_object_entry(peeled))      /* object packed? */
1959                 add_object_entry(sha1, OBJ_TAG, NULL, 0);
1960         return 0;
1961 }
1962
1963 static void prepare_pack(int window, int depth)
1964 {
1965         struct object_entry **delta_list;
1966         uint32_t i, nr_deltas;
1967         unsigned n;
1968
1969         get_object_details();
1970
1971         /*
1972          * If we're locally repacking then we need to be doubly careful
1973          * from now on in order to make sure no stealth corruption gets
1974          * propagated to the new pack.  Clients receiving streamed packs
1975          * should validate everything they get anyway so no need to incur
1976          * the additional cost here in that case.
1977          */
1978         if (!pack_to_stdout)
1979                 do_check_packed_object_crc = 1;
1980
1981         if (!nr_objects || !window || !depth)
1982                 return;
1983
1984         delta_list = xmalloc(nr_objects * sizeof(*delta_list));
1985         nr_deltas = n = 0;
1986
1987         for (i = 0; i < nr_objects; i++) {
1988                 struct object_entry *entry = objects + i;
1989
1990                 if (entry->delta)
1991                         /* This happens if we decided to reuse existing
1992                          * delta from a pack.  "reuse_delta &&" is implied.
1993                          */
1994                         continue;
1995
1996                 if (entry->size < 50)
1997                         continue;
1998
1999                 if (entry->no_try_delta)
2000                         continue;
2001
2002                 if (!entry->preferred_base) {
2003                         nr_deltas++;
2004                         if (entry->type < 0)
2005                                 die("unable to get type of object %s",
2006                                     sha1_to_hex(entry->idx.sha1));
2007                 } else {
2008                         if (entry->type < 0) {
2009                                 /*
2010                                  * This object is not found, but we
2011                                  * don't have to include it anyway.
2012                                  */
2013                                 continue;
2014                         }
2015                 }
2016
2017                 delta_list[n++] = entry;
2018         }
2019
2020         if (nr_deltas && n > 1) {
2021                 unsigned nr_done = 0;
2022                 if (progress)
2023                         progress_state = start_progress("Compressing objects",
2024                                                         nr_deltas);
2025                 qsort(delta_list, n, sizeof(*delta_list), type_size_sort);
2026                 ll_find_deltas(delta_list, n, window+1, depth, &nr_done);
2027                 stop_progress(&progress_state);
2028                 if (nr_done != nr_deltas)
2029                         die("inconsistency with delta count");
2030         }
2031         free(delta_list);
2032 }
2033
2034 static int git_pack_config(const char *k, const char *v, void *cb)
2035 {
2036         if (!strcmp(k, "pack.window")) {
2037                 window = git_config_int(k, v);
2038                 return 0;
2039         }
2040         if (!strcmp(k, "pack.windowmemory")) {
2041                 window_memory_limit = git_config_ulong(k, v);
2042                 return 0;
2043         }
2044         if (!strcmp(k, "pack.depth")) {
2045                 depth = git_config_int(k, v);
2046                 return 0;
2047         }
2048         if (!strcmp(k, "pack.compression")) {
2049                 int level = git_config_int(k, v);
2050                 if (level == -1)
2051                         level = Z_DEFAULT_COMPRESSION;
2052                 else if (level < 0 || level > Z_BEST_COMPRESSION)
2053                         die("bad pack compression level %d", level);
2054                 pack_compression_level = level;
2055                 pack_compression_seen = 1;
2056                 return 0;
2057         }
2058         if (!strcmp(k, "pack.deltacachesize")) {
2059                 max_delta_cache_size = git_config_int(k, v);
2060                 return 0;
2061         }
2062         if (!strcmp(k, "pack.deltacachelimit")) {
2063                 cache_max_small_delta_size = git_config_int(k, v);
2064                 return 0;
2065         }
2066         if (!strcmp(k, "pack.threads")) {
2067                 delta_search_threads = git_config_int(k, v);
2068                 if (delta_search_threads < 0)
2069                         die("invalid number of threads specified (%d)",
2070                             delta_search_threads);
2071 #ifdef NO_PTHREADS
2072                 if (delta_search_threads != 1)
2073                         warning("no threads support, ignoring %s", k);
2074 #endif
2075                 return 0;
2076         }
2077         if (!strcmp(k, "pack.indexversion")) {
2078                 pack_idx_opts.version = git_config_int(k, v);
2079                 if (pack_idx_opts.version > 2)
2080                         die("bad pack.indexversion=%"PRIu32,
2081                             pack_idx_opts.version);
2082                 return 0;
2083         }
2084         return git_default_config(k, v, cb);
2085 }
2086
2087 static void read_object_list_from_stdin(void)
2088 {
2089         char line[40 + 1 + PATH_MAX + 2];
2090         unsigned char sha1[20];
2091
2092         for (;;) {
2093                 if (!fgets(line, sizeof(line), stdin)) {
2094                         if (feof(stdin))
2095                                 break;
2096                         if (!ferror(stdin))
2097                                 die("fgets returned NULL, not EOF, not error!");
2098                         if (errno != EINTR)
2099                                 die_errno("fgets");
2100                         clearerr(stdin);
2101                         continue;
2102                 }
2103                 if (line[0] == '-') {
2104                         if (get_sha1_hex(line+1, sha1))
2105                                 die("expected edge sha1, got garbage:\n %s",
2106                                     line);
2107                         add_preferred_base(sha1);
2108                         continue;
2109                 }
2110                 if (get_sha1_hex(line, sha1))
2111                         die("expected sha1, got garbage:\n %s", line);
2112
2113                 add_preferred_base_object(line+41);
2114                 add_object_entry(sha1, 0, line+41, 0);
2115         }
2116 }
2117
2118 #define OBJECT_ADDED (1u<<20)
2119
2120 static void show_commit(struct commit *commit, void *data)
2121 {
2122         add_object_entry(commit->object.sha1, OBJ_COMMIT, NULL, 0);
2123         commit->object.flags |= OBJECT_ADDED;
2124 }
2125
2126 static void show_object(struct object *obj,
2127                         const struct name_path *path, const char *last,
2128                         void *data)
2129 {
2130         char *name = path_name(path, last);
2131
2132         add_preferred_base_object(name);
2133         add_object_entry(obj->sha1, obj->type, name, 0);
2134         obj->flags |= OBJECT_ADDED;
2135
2136         /*
2137          * We will have generated the hash from the name,
2138          * but not saved a pointer to it - we can free it
2139          */
2140         free((char *)name);
2141 }
2142
2143 static void show_edge(struct commit *commit)
2144 {
2145         add_preferred_base(commit->object.sha1);
2146 }
2147
2148 struct in_pack_object {
2149         off_t offset;
2150         struct object *object;
2151 };
2152
2153 struct in_pack {
2154         int alloc;
2155         int nr;
2156         struct in_pack_object *array;
2157 };
2158
2159 static void mark_in_pack_object(struct object *object, struct packed_git *p, struct in_pack *in_pack)
2160 {
2161         in_pack->array[in_pack->nr].offset = find_pack_entry_one(object->sha1, p);
2162         in_pack->array[in_pack->nr].object = object;
2163         in_pack->nr++;
2164 }
2165
2166 /*
2167  * Compare the objects in the offset order, in order to emulate the
2168  * "git rev-list --objects" output that produced the pack originally.
2169  */
2170 static int ofscmp(const void *a_, const void *b_)
2171 {
2172         struct in_pack_object *a = (struct in_pack_object *)a_;
2173         struct in_pack_object *b = (struct in_pack_object *)b_;
2174
2175         if (a->offset < b->offset)
2176                 return -1;
2177         else if (a->offset > b->offset)
2178                 return 1;
2179         else
2180                 return hashcmp(a->object->sha1, b->object->sha1);
2181 }
2182
2183 static void add_objects_in_unpacked_packs(struct rev_info *revs)
2184 {
2185         struct packed_git *p;
2186         struct in_pack in_pack;
2187         uint32_t i;
2188
2189         memset(&in_pack, 0, sizeof(in_pack));
2190
2191         for (p = packed_git; p; p = p->next) {
2192                 const unsigned char *sha1;
2193                 struct object *o;
2194
2195                 if (!p->pack_local || p->pack_keep)
2196                         continue;
2197                 if (open_pack_index(p))
2198                         die("cannot open pack index");
2199
2200                 ALLOC_GROW(in_pack.array,
2201                            in_pack.nr + p->num_objects,
2202                            in_pack.alloc);
2203
2204                 for (i = 0; i < p->num_objects; i++) {
2205                         sha1 = nth_packed_object_sha1(p, i);
2206                         o = lookup_unknown_object(sha1);
2207                         if (!(o->flags & OBJECT_ADDED))
2208                                 mark_in_pack_object(o, p, &in_pack);
2209                         o->flags |= OBJECT_ADDED;
2210                 }
2211         }
2212
2213         if (in_pack.nr) {
2214                 qsort(in_pack.array, in_pack.nr, sizeof(in_pack.array[0]),
2215                       ofscmp);
2216                 for (i = 0; i < in_pack.nr; i++) {
2217                         struct object *o = in_pack.array[i].object;
2218                         add_object_entry(o->sha1, o->type, "", 0);
2219                 }
2220         }
2221         free(in_pack.array);
2222 }
2223
2224 static int has_sha1_pack_kept_or_nonlocal(const unsigned char *sha1)
2225 {
2226         static struct packed_git *last_found = (void *)1;
2227         struct packed_git *p;
2228
2229         p = (last_found != (void *)1) ? last_found : packed_git;
2230
2231         while (p) {
2232                 if ((!p->pack_local || p->pack_keep) &&
2233                         find_pack_entry_one(sha1, p)) {
2234                         last_found = p;
2235                         return 1;
2236                 }
2237                 if (p == last_found)
2238                         p = packed_git;
2239                 else
2240                         p = p->next;
2241                 if (p == last_found)
2242                         p = p->next;
2243         }
2244         return 0;
2245 }
2246
2247 static void loosen_unused_packed_objects(struct rev_info *revs)
2248 {
2249         struct packed_git *p;
2250         uint32_t i;
2251         const unsigned char *sha1;
2252
2253         for (p = packed_git; p; p = p->next) {
2254                 if (!p->pack_local || p->pack_keep)
2255                         continue;
2256
2257                 if (open_pack_index(p))
2258                         die("cannot open pack index");
2259
2260                 for (i = 0; i < p->num_objects; i++) {
2261                         sha1 = nth_packed_object_sha1(p, i);
2262                         if (!locate_object_entry(sha1) &&
2263                                 !has_sha1_pack_kept_or_nonlocal(sha1))
2264                                 if (force_object_loose(sha1, p->mtime))
2265                                         die("unable to force loose object");
2266                 }
2267         }
2268 }
2269
2270 static void get_object_list(int ac, const char **av)
2271 {
2272         struct rev_info revs;
2273         char line[1000];
2274         int flags = 0;
2275
2276         init_revisions(&revs, NULL);
2277         save_commit_buffer = 0;
2278         setup_revisions(ac, av, &revs, NULL);
2279
2280         while (fgets(line, sizeof(line), stdin) != NULL) {
2281                 int len = strlen(line);
2282                 if (len && line[len - 1] == '\n')
2283                         line[--len] = 0;
2284                 if (!len)
2285                         break;
2286                 if (*line == '-') {
2287                         if (!strcmp(line, "--not")) {
2288                                 flags ^= UNINTERESTING;
2289                                 continue;
2290                         }
2291                         die("not a rev '%s'", line);
2292                 }
2293                 if (handle_revision_arg(line, &revs, flags, 1))
2294                         die("bad revision '%s'", line);
2295         }
2296
2297         if (prepare_revision_walk(&revs))
2298                 die("revision walk setup failed");
2299         mark_edges_uninteresting(revs.commits, &revs, show_edge);
2300         traverse_commit_list(&revs, show_commit, show_object, NULL);
2301
2302         if (keep_unreachable)
2303                 add_objects_in_unpacked_packs(&revs);
2304         if (unpack_unreachable)
2305                 loosen_unused_packed_objects(&revs);
2306 }
2307
2308 int cmd_pack_objects(int argc, const char **argv, const char *prefix)
2309 {
2310         int use_internal_rev_list = 0;
2311         int thin = 0;
2312         int all_progress_implied = 0;
2313         uint32_t i;
2314         const char **rp_av;
2315         int rp_ac_alloc = 64;
2316         int rp_ac;
2317
2318         read_replace_refs = 0;
2319
2320         rp_av = xcalloc(rp_ac_alloc, sizeof(*rp_av));
2321
2322         rp_av[0] = "pack-objects";
2323         rp_av[1] = "--objects"; /* --thin will make it --objects-edge */
2324         rp_ac = 2;
2325
2326         reset_pack_idx_option(&pack_idx_opts);
2327         git_config(git_pack_config, NULL);
2328         if (!pack_compression_seen && core_compression_seen)
2329                 pack_compression_level = core_compression_level;
2330
2331         progress = isatty(2);
2332         for (i = 1; i < argc; i++) {
2333                 const char *arg = argv[i];
2334
2335                 if (*arg != '-')
2336                         break;
2337
2338                 if (!strcmp("--non-empty", arg)) {
2339                         non_empty = 1;
2340                         continue;
2341                 }
2342                 if (!strcmp("--local", arg)) {
2343                         local = 1;
2344                         continue;
2345                 }
2346                 if (!strcmp("--incremental", arg)) {
2347                         incremental = 1;
2348                         continue;
2349                 }
2350                 if (!strcmp("--honor-pack-keep", arg)) {
2351                         ignore_packed_keep = 1;
2352                         continue;
2353                 }
2354                 if (!prefixcmp(arg, "--compression=")) {
2355                         char *end;
2356                         int level = strtoul(arg+14, &end, 0);
2357                         if (!arg[14] || *end)
2358                                 usage(pack_usage);
2359                         if (level == -1)
2360                                 level = Z_DEFAULT_COMPRESSION;
2361                         else if (level < 0 || level > Z_BEST_COMPRESSION)
2362                                 die("bad pack compression level %d", level);
2363                         pack_compression_level = level;
2364                         continue;
2365                 }
2366                 if (!prefixcmp(arg, "--max-pack-size=")) {
2367                         pack_size_limit_cfg = 0;
2368                         if (!git_parse_ulong(arg+16, &pack_size_limit))
2369                                 usage(pack_usage);
2370                         continue;
2371                 }
2372                 if (!prefixcmp(arg, "--window=")) {
2373                         char *end;
2374                         window = strtoul(arg+9, &end, 0);
2375                         if (!arg[9] || *end)
2376                                 usage(pack_usage);
2377                         continue;
2378                 }
2379                 if (!prefixcmp(arg, "--window-memory=")) {
2380                         if (!git_parse_ulong(arg+16, &window_memory_limit))
2381                                 usage(pack_usage);
2382                         continue;
2383                 }
2384                 if (!prefixcmp(arg, "--threads=")) {
2385                         char *end;
2386                         delta_search_threads = strtoul(arg+10, &end, 0);
2387                         if (!arg[10] || *end || delta_search_threads < 0)
2388                                 usage(pack_usage);
2389 #ifdef NO_PTHREADS
2390                         if (delta_search_threads != 1)
2391                                 warning("no threads support, "
2392                                         "ignoring %s", arg);
2393 #endif
2394                         continue;
2395                 }
2396                 if (!prefixcmp(arg, "--depth=")) {
2397                         char *end;
2398                         depth = strtoul(arg+8, &end, 0);
2399                         if (!arg[8] || *end)
2400                                 usage(pack_usage);
2401                         continue;
2402                 }
2403                 if (!strcmp("--progress", arg)) {
2404                         progress = 1;
2405                         continue;
2406                 }
2407                 if (!strcmp("--all-progress", arg)) {
2408                         progress = 2;
2409                         continue;
2410                 }
2411                 if (!strcmp("--all-progress-implied", arg)) {
2412                         all_progress_implied = 1;
2413                         continue;
2414                 }
2415                 if (!strcmp("-q", arg)) {
2416                         progress = 0;
2417                         continue;
2418                 }
2419                 if (!strcmp("--no-reuse-delta", arg)) {
2420                         reuse_delta = 0;
2421                         continue;
2422                 }
2423                 if (!strcmp("--no-reuse-object", arg)) {
2424                         reuse_object = reuse_delta = 0;
2425                         continue;
2426                 }
2427                 if (!strcmp("--delta-base-offset", arg)) {
2428                         allow_ofs_delta = 1;
2429                         continue;
2430                 }
2431                 if (!strcmp("--stdout", arg)) {
2432                         pack_to_stdout = 1;
2433                         continue;
2434                 }
2435                 if (!strcmp("--revs", arg)) {
2436                         use_internal_rev_list = 1;
2437                         continue;
2438                 }
2439                 if (!strcmp("--keep-unreachable", arg)) {
2440                         keep_unreachable = 1;
2441                         continue;
2442                 }
2443                 if (!strcmp("--unpack-unreachable", arg)) {
2444                         unpack_unreachable = 1;
2445                         continue;
2446                 }
2447                 if (!strcmp("--include-tag", arg)) {
2448                         include_tag = 1;
2449                         continue;
2450                 }
2451                 if (!strcmp("--unpacked", arg) ||
2452                     !strcmp("--reflog", arg) ||
2453                     !strcmp("--all", arg)) {
2454                         use_internal_rev_list = 1;
2455                         if (rp_ac >= rp_ac_alloc - 1) {
2456                                 rp_ac_alloc = alloc_nr(rp_ac_alloc);
2457                                 rp_av = xrealloc(rp_av,
2458                                                  rp_ac_alloc * sizeof(*rp_av));
2459                         }
2460                         rp_av[rp_ac++] = arg;
2461                         continue;
2462                 }
2463                 if (!strcmp("--thin", arg)) {
2464                         use_internal_rev_list = 1;
2465                         thin = 1;
2466                         rp_av[1] = "--objects-edge";
2467                         continue;
2468                 }
2469                 if (!prefixcmp(arg, "--index-version=")) {
2470                         char *c;
2471                         pack_idx_opts.version = strtoul(arg + 16, &c, 10);
2472                         if (pack_idx_opts.version > 2)
2473                                 die("bad %s", arg);
2474                         if (*c == ',')
2475                                 pack_idx_opts.off32_limit = strtoul(c+1, &c, 0);
2476                         if (*c || pack_idx_opts.off32_limit & 0x80000000)
2477                                 die("bad %s", arg);
2478                         continue;
2479                 }
2480                 if (!strcmp(arg, "--keep-true-parents")) {
2481                         grafts_replace_parents = 0;
2482                         continue;
2483                 }
2484                 usage(pack_usage);
2485         }
2486
2487         /* Traditionally "pack-objects [options] base extra" failed;
2488          * we would however want to take refs parameter that would
2489          * have been given to upstream rev-list ourselves, which means
2490          * we somehow want to say what the base name is.  So the
2491          * syntax would be:
2492          *
2493          * pack-objects [options] base <refs...>
2494          *
2495          * in other words, we would treat the first non-option as the
2496          * base_name and send everything else to the internal revision
2497          * walker.
2498          */
2499
2500         if (!pack_to_stdout)
2501                 base_name = argv[i++];
2502
2503         if (pack_to_stdout != !base_name)
2504                 usage(pack_usage);
2505
2506         if (!pack_to_stdout && !pack_size_limit)
2507                 pack_size_limit = pack_size_limit_cfg;
2508         if (pack_to_stdout && pack_size_limit)
2509                 die("--max-pack-size cannot be used to build a pack for transfer.");
2510         if (pack_size_limit && pack_size_limit < 1024*1024) {
2511                 warning("minimum pack size limit is 1 MiB");
2512                 pack_size_limit = 1024*1024;
2513         }
2514
2515         if (!pack_to_stdout && thin)
2516                 die("--thin cannot be used to build an indexable pack.");
2517
2518         if (keep_unreachable && unpack_unreachable)
2519                 die("--keep-unreachable and --unpack-unreachable are incompatible.");
2520
2521         if (progress && all_progress_implied)
2522                 progress = 2;
2523
2524         prepare_packed_git();
2525
2526         if (progress)
2527                 progress_state = start_progress("Counting objects", 0);
2528         if (!use_internal_rev_list)
2529                 read_object_list_from_stdin();
2530         else {
2531                 rp_av[rp_ac] = NULL;
2532                 get_object_list(rp_ac, rp_av);
2533         }
2534         cleanup_preferred_base();
2535         if (include_tag && nr_result)
2536                 for_each_ref(add_ref_tag, NULL);
2537         stop_progress(&progress_state);
2538
2539         if (non_empty && !nr_result)
2540                 return 0;
2541         if (nr_result)
2542                 prepare_pack(window, depth);
2543         write_pack_file();
2544         if (progress)
2545                 fprintf(stderr, "Total %"PRIu32" (delta %"PRIu32"),"
2546                         " reused %"PRIu32" (delta %"PRIu32")\n",
2547                         written, written_delta, reused, reused_delta);
2548         return 0;
2549 }